Force required to level out a bookshelf with weights on it

Leif and Paige are rearranging the heights of their movable bookshelves; they remove one of the 2kg, 0.6 m long shelves by the two of them holding opposite ends. A 5.0 kg stack of books is piled up on the shelf 0.2 m from Leif. How much force must Leif and Paige each exert to hold the shelf level?

2. Relevant equations

F = ma

3. The attempt at a solution

F = 1 * 5 * 10
F = 50 N up from Leif

F = 10 N up from Paige

I don't know how to calculate the mass in

Help please, i need like step by step help please, i don't think very good thanks